|
|
|
|
>>
>>
>>
Profiling 62 cm small end diameter [Holz-Kurier report nr. 49 dated 2006-12-07]
|
|
|
Profiling 62 cm small end diameter [Holz-Kurier report nr. 49 dated 2006-12-07]
|
|
Sawmill reconstruction under production conditionsHolz-Kurier report from Wolfsberg/Carinthia |
|
|
Does this represent the future for processing large diameter logs ? In Wolfsberg, the Holzindustrie Offner started a worldwide unique profiling line: small end diameters up to maximum 62 cm can be processed in a large quantity, producing lumber with smooth surface, high accuracy and high recovery. The sideboard optimising system integrated in the sawline makes it possible to gain even more recovery and Euros out of the valuable log envelopes.
Round log reality asked for solutions. These parameters were included in the requirement specification for the 40 Mio. € investment drawn up by Councillor of commerce DI Hans Michael Offner. The task of his project team under the direction of plant manager Rochus Sachadonig and his representative Markus Wernig was now to put these specifications into practice in cooperation with the main suppliers Linck, Oberkirch/Germany and the Maschinenfabrik Springer, Friesach/Austria. “We really had to come up with something. The mountain forests south of the main alpine range are rich in large diameter logs, the matured forests increase. We already arrived at 27 cm average diameter”, explains Offner who looked for a solution to economically make use of the round log quantities available. “The higher price for round logs now contributes that valuable stocks of large diameter logs are finally usable.”
It had to be chipper canters. The chairman of the Austrian and European sawmill industry was bothered by the low recovery when using gang- and bandsaws. Moreover since 1982 Offner has many years of experience with the profiling technology. “We were the first producing eight sideboards – but so far had to accept compromises with regards to recovery when processing logs with more than 35 cm small end diameter”, explains Offner. Now the following solution is available: One sideboard optimising system is installed after each of the two Linck V50 chipper canters which are fed with information from the two Sprescan 3D-cant scanners supplied by Sprecher Automation.
Sideboard optimisation. Up to three sideboards per side can be shifted in width and position in the virtual 3D-log pattern until value or recovery are optimised: out of logs with up to 62 cm top end diameter. In addition the conditions for processing large diameter logs were optimised by installing new profiler units VPK and bigger saw units to avoid tear-out in front of and behind the knots – a problem which Offner still had on the Linck-line installed in 1982 (up to 43 cm top end).
|
|
Responsible for the production of up to 350
boards per minute - operator in front of monitors
|
Two-sided cants are chipped - sideboards
are already visually optimised in width and
position in front of the first saw unit CSMK.
|
|
|
|
|
|
|
"Halftime": view of the sawline until the resaws
and the bypass.
PHOTOS: EBNER; GRAPHICAL DESIGN: OFFNER
|
"Undreamed-of possibilities with direct processing."
Hans Michael Offner
|
|
High feed speeds. Offner assumes that this machine combination now allows to work with high speeds even with diameters from 35 up to 55 cm. “Feed speed is frequency convertor controlled and ranges from 45 to 130 m/min – so we are competitive with small diameter logs and play in our own league when processing large diameter logs”, states Offner.
Separate production line “The drawback with processing large diameter logs is the relatively high percentage of bad round log qualities”, admits Offner, who however has an additional filleting possibility with the triple bandsaw supplied by Esterer WD, Reutlingen/Germany and the TC Maschinenbau conveyors installed in December 2005. “With this equipment it is possible to handle and to bundle composite lumber rejects. But I assume that we can practically finish many products in the sawline with the two MKV double arbor gangs. The bandsaw can split products of any size upright and horizontal – they are controlled, bundled, strapped and packeted”, explains Offner.
New construction and parallel production. Profiling of large diameter logs with highest capacity was realised at the Offner sawmill with several machine prototypes, reinforcements and adaptations supplied and carried out by the main suppliers Linck and Springer. It is specially remarkable that the whole reconstruction of the sawmill building, the installation of the sawline, the corresponding modification of the round log loading and feeding station, the connection of the existing lumber sorting plant and the link-up of the new centre- and sideboard sorting plant were carried out under production conditions.
The whole exhaust ventilation system for the sawline was supplied by Scheuch, Aurolzmünster/Germany.
Besides the suppliers, Offner particularly thanks project coordinator DI Alfons Rink and his regular sawmill staff who succeeded in processing the first log exactly on the schedule date, i.e. November 10, 2006. The second shift already started production in week 48.
Large end ahead. The new sawmill is equipped with a Linck round log feeding station which turns the logs large end leading – non-suitable logs can be sorted out. Underneath the operator’s cabin, a Sprecher Sprescan-3D scanner is measuring the log shape for optimum log orientation in front of the first V50 chipper canter. The two-sided cant is then measured, turned and further processed in the second V50 chipper canter.
Two CSMK saw units follow to complete the precut with four plus two sideboards. Another four sideboards are possible in the recut and an additional CSMK saw unit even allows core- and split cutting. A MKV double arbor gang is also installed in line for producing square timber. In case core boards are sawn, the products are fed via bypass to a second double arbor gang MKV still to be installed.
To tame torrent of boards. The 350 boards per minute, produced with a maximum feed speed of 140 m/min., have to be taken by the new and the two existing Springer sorting systems (see Holzkurier report nr. 47, page 16). Six belt conveyors hand the sideboards over to the sorting stations, the main products are transferred in the centre.
|
|
|
|
Due to the smooth production transfer from the existing to the new profiling line and despite the problems with the supply of round logs caused by the weather, it will again be possible to process only shortly under the previous year’s capacity of 470.000 m³ logs.
Up to 800.000 m³ round logs/year. Processing of 600.000 m³ round logs in one and a half shifts is scheduled for 2007. It is envisaged to increase this capacity up to 800.000 m³ round logs in 2009. “This would represent the utilisation of the maximum supply capacities from the vicinity and to fully exhaust the 60.000 m³ of round log capacity. Last winter showed how weather-dependent the domestic hightech sawmills are: Even future production and storage have to be handled like a concertina – much with utmost log supply and less with a shortage of logs.
If required: full service for forest owners. Offner intends to purchase 80 % of the required round logs within a distance of 100 km. “We have purchasing agents in each district who organise everything for the forest owners, from harvest to transport”, mobilises Offner on his own account.
He assumes that the sawline is capable to directly process 99 % of the offered diameter range. Logs being too large could be reduced to 60 cm small end diameter. He even points out: “Exchanging logs with bandsaw mills would also be possible”.
Significant recovery increase. The average diameter will increase from 27 cm to 30 cm. Offner envisages to increase recovery from presently 62,5 % (chipper canter and gangsaw) to remarkable 65,5%.
Offner invested the total sum of about 40 Mio. € in the Wolfsberg mill. “This fact of high costs alone will scare most competitors off to install something similar complex/sophisticated”, answers Offner winking to the question whether this sawline will be the starting signal for a completely new kind of large log processing.
Higher drying capacity. The next extension level is increasing the present kiln drying capacity of 250.000 m³ of lumber/year by additional 50 %. According to Offner, a pellet producing plant is still at its beginnings, but could be most probably be realised in 2007/2008. Favoured capacity: 40.000 tons/year. Additional 12 MW-heat for drying chips and dry kilns should be made available by the contractual partner and neighbour Mondi Packaging, Frantschach.
Customised production. Offner doesn’t have any further projects on his priority list: “Our future motto is the same as it has been in the past: Don’t compete with your customers.”A still secret future plan is the production of wood plastics composites (WPC) for handles of the own tool production which doesn’t compete with any customer. GE
|
|
|
|
 |
|
|
|
|
Profiling 62 cm small end diameter [Holz-Kurier report nr. 49 dated 2006-12-07]
|
|
|
|
|
|
|
